package com.chd.utils;

import cn.hutool.core.util.IdUtil;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

import static com.chd.utils.RedisConstants.DATA_CENTER_ID;
import static com.chd.utils.RedisConstants.WORKER_ID;

public class SimpleRedisLock implements ILock{
//    @Resource
    private StringRedisTemplate stringRedisTemplate;

    private String name;

    private static final String KEY_PREFIX = "lock:";

    private static final String ID_PREFIX = IdUtil.getSnowflake(WORKER_ID, DATA_CENTER_ID).nextIdStr();

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;

    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }


    @Override
    public boolean tryLock(long timeoutSec) {
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        Boolean success = stringRedisTemplate
                .opsForValue()
                .setIfAbsent(KEY_PREFIX + name,
                        threadId,
                        timeoutSec,
                        TimeUnit.SECONDS);
        // 注意自动拆箱
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock() {
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//        if (stringRedisTemplate.opsForValue().get(KEY_PREFIX + name).equals(threadId)) {
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
        // 调用Lua脚本
        stringRedisTemplate
                .execute(UNLOCK_SCRIPT,
                        Collections.singletonList(KEY_PREFIX + name),
                        ID_PREFIX + Thread.currentThread().getId());
    }
}
